Method and device for controlling transmission power for uplink control channel in carrier aggregation system

ABSTRACT

Provided are a method of controlling transmission power for an uplink control channel for a terminal to which a plurality of cells are assigned, and a device using the method. The method receives a first set of parameters and a second set of parameters that are used for determining transmission power for the uplink control channel and determines the transmission power for the uplink control channel by using the first set of parameters or the second set of parameters, wherein the first set of parameters or the second set of parameters is used according to one of the cells to which the uplink control channel is transmitted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/385,562, filed on Dec. 20, 2016, now U.S. Pat. No. 9,907,030, whichis a continuation of U.S. patent application Ser. No. 14/425,294, filedon Mar. 2, 2015, now U.S. Pat. No. 9,554,372, which is the NationalStage filing under 35 U.S.C. 371 of International Application No.PCT/KR2013/008128, filed on Sep. 9, 2013, which claims the benefit ofU.S. Provisional Application No. 61/697,811, filed on Sep. 7, 2012, thecontents of which are all hereby incorporated by reference herein intheir entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method of controlling transmission power of an uplinkcontrol channel in a carrier aggregation system, and an apparatus usingthe method.

Related Art

Long term evolution (LTE) based on 3rd generation partnership project(3GPP) technical specification (TS) release 8 is a promisingnext-generation mobile communication standard.

Although a carrier having various bandwidths is provided in LTE, it ispremised that communication is performed basically using one carrier.

Meanwhile, 3GPP LTE-advanced (A) which is an evolution of 3GPP LTE isunder development. A carrier aggregation (CA) is a technique employed inthe 3GPP LTE-A.

The CA uses a plurality of component carriers (CCs). The CC is definedwith a center frequency and a bandwidth. One downlink (DL) CC or a pairof an uplink (UL) CC and a DL CC corresponds to one cell. When a userequipment receives a service by using a plurality of DL CCs, it can besaid that the user equipment receives the service from a plurality ofserving cells.

Conventionally, a user equipment to which a plurality of serving cellsare configured can transmit an uplink control channel only through aspecific cell called a primary cell among the plurality of servingcells. Therefore, it is specified that transmission power of the uplinkcontrol channel is determined by considering only the primary cell.

However, a future wireless communication system can transmit the uplinkcontrol channel also in different cells other than the primary cellamong a plurality of aggregated cells. There is a need for a method andapparatus for controlling transmission power of the uplink controlchannel, which can be applied to the future wireless communicationsystem.

SUMMARY OF THE INVENTION

The present invention provides a method of controlling transmissionpower of an uplink control channel in a carrier aggregation system, andan apparatus using the method.

In an aspect, a method of controlling transmission power of an uplinkcontrol channel of a user equipment for which a plurality of cells areconfigured is provided. The method comprises receiving a first parameterset and a second parameter set which are used to determine thetransmission power of the uplink control channel; and determining thetransmission power of the uplink control channel by using the firstparameter set or the second parameter set. The first parameter set orthe second parameter set is used according to a cell in which the uplinkcontrol channel is transmitted among the plurality of cells.

In another aspect, a user equipment is provided. The user equipmentcomprises a radio frequency (RF) unit for transmitting and receiving aradio signal; and a processor operatively coupled to the RF unit. Theprocessor is configured for: receiving a first parameter set and asecond parameter set which are used to determine the transmission powerof the uplink control channel; and determining the transmission power ofthe uplink control channel by using the first parameter set or thesecond parameter set, wherein the first parameter set or the secondparameter set is used according to a cell in which the uplink controlchannel is transmitted among the plurality of cells.

Transmission power of an uplink control channel can be effectivelyconfigured in a carrier aggregation system in which a plurality ofserving cells are configured for a user equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a frequency division duplex (FDD) radioframe.

FIG. 2 shows a structure of a time division duplex (TDD) radio frame.

FIG. 3 shows an example of a resource grid for one downlink (DL) slot.

FIG. 4 shows a structure of a DL subframe.

FIG. 5 shows a structure of an uplink (UL) subframe.

FIG. 6 shows a channel structure of a physical uplink control channel(PUCCH) format 1b in a normal cyclic prefix (CP) case.

FIG. 7 shows a channel structure of PUCCH formats 2/2a/2b in a normal CPcase.

FIG. 8 shows a PUCCH format 3 based on block spreading.

FIG. 9 shows an example of comparing a single carrier system and acarrier aggregation system.

FIG. 10 shows a PUCCH power control method according to an embodiment ofthe present invention.

FIG. 11 shows an example of a method of determining PUSCH transmissionpower when a PUCCH can be transmitted also in a secondary cell.

FIG. 12 is a block diagram showing a wireless device according to anembodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A user equipment (UE) may be fixed or mobile, and may be referred to asanother terminology, such as a mobile station (MS), a mobile terminal(MT), a user terminal (UT), a subscriber station (SS), a wirelessdevice, a personal digital assistant (PDA), a wireless modem, a handhelddevice, etc.

A base station (BS) is generally a fixed station that communicates withthe UE and may be referred to as another terminology, such as an evolvedNode-B (eNB), a base transceiver system (BTS), an access point, etc.

A communication from the BS to the UE is called a downlink (DL), and acommunication from the UE to the BS is called an uplink (UL). A wirelesscommunication system including the BS and the UE may be a time divisionduplex (TDD) system or a frequency division duplex (FDD) system. The TDDsystem is a wireless communication system for performing UL and DLtransmission/reception by using different times at the same frequencyband. The FDD system is a wireless communication system capable ofsimultaneously performing UL and DL transmission/reception by usingdifferent frequency bands. The wireless communication system can performcommunication by using a radio frame.

FIG. 1 shows a structure of an FDD radio frame.

The FDD radio frame (hereinafter, simply referred to as FDD frame)includes 10 subframes. One subframe includes two consecutive slots.Slots included in the radio frame are indexed from 0 to 19. A timerequired to transmit one subframe is defined as a transmission timeinterval (TTI). The TTI may be a minimum scheduling unit. For example,one subframe may have a length of 1 milliseconds (ms), and one slot mayhave a length of 0.5 ms. An FDD radio frame may include the same numberof (for example, 10) uplink subframes and downlink subframes atdifferent frequency bands.

FIG. 2 shows a structure of a TDD radio frame.

Referring to FIG. 2, the TDD radio frame (hereinafter, TDD frame)includes 10 subframes. When subframes are indexed from 0 to 9, asubframe having an index #1 and an index #6 is called a special subframe(simply referred to as an S subframe), and includes a downlink pilottime slot (DwPTS), a guard period (GP), and an uplink pilot time slot(UpPTS). The DwPTS is used in a UE for initial cell search,synchronization, or channel estimation. The UpPTS is used in a BS forchannel estimation and uplink transmission synchronization of the UE.The GP is a period for removing interference which occurs in an uplinkdue to a multi-path delay of a downlink signal between the uplink and adownlink. [31] In the TDD frame, a downlink (DL) subframe and an uplink(UL) subframe coexist. Table 1 below shows an example of a UL-DLconfiguration of a radio frame.

TABLE 1 Uplink- Downlink- downlink to-Uplink config- Switch-pointSubframe n uration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D SU U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D SU U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D6 5 ms D S U U U D S U U D

In Table 1 above, ‘D’ denotes a DL subframe, ‘U’ denotes a UL subframe,and ‘S’ denotes a special subframe. Upon receiving the UL-DLconfiguration from the BS, the UE can know whether each subframe is a DLsubframe or a UL subframe in the TDD subframe. Hereinafter, a UL-DLconfiguration N (where N is any one value from 0 to 6) may use Table 1above by reference.

Meanwhile, the special subframe may be any one of configurations shownin the following table.

TABLE 2 Normal CP (downlink) Extended CP(downlink) Special UpPTS UpPTSsubframe Normal CP Extended CP Normal CP Extended CP configuration DwPTS(uplink) (uplink) DwPTS (uplink) (uplink) 0  6592 · T_(s) 2192 · T_(s)2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 1 19760 · T_(s)20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600 ·T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 · T_(s) 5  6592 ·T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 · T_(s) 23040 ·T_(s) 7 21952 · T_(s) — — — 8 24144 · T_(s) — — —

In Table 2, T_(s) has a relation of: 307200T_(s)=10 ms (millisecond).

FIG. 3 shows an example of a resource grid for one DL slot.

Referring to FIG. 3, the DL slot includes a plurality of orthogonalfrequency division multiplexing (OFDM) symbols in a time domain, andincludes N_(RB) resource blocks (RBs) in a frequency domain. The RB is aresource allocation unit, and includes one slot in the time domain andincludes a plurality of subcarriers in the frequency domain. The numberN_(RB) of RBs included in the DL slot depends on a DL transmissionbandwidth configured in a cell. For example, in the LTE system, N_(RB)may be any one value in the range of 6 to 110. A structure of a UL slotmay be the same as the aforementioned structure of the DL slot. [41]Each element on the resource grid is referred to as a resource element(RE). The RE on the resource grid can be identified by an index pair(k,l) within the slot. Herein, k(k=0, . . . , N_(RB)×12−1) denotes asubcarrier index in the frequency domain, and l(l=0, . . . , 6) denotesan OFDM symbol index in the time domain.

Although it is described in FIG. 3 that one RB includes 7×12 REsconsisting of 7 OFDM symbols in the time domain and 12 subcarriers inthe frequency domain for example, the number of OFDM symbols and thenumber of subcarriers in the RB are not limited thereto. The number ofOFDM symbols and the number of subcarriers may change variouslydepending on a cyclic prefix (CP) length, a frequency spacing, etc. Thenumber of subcarriers in one OFDM symbol may be selected from 128, 256,512, 1024, 1536, and 2048.

FIG. 4 shows a structure of a DL subframe.

Referring to FIG. 4, the DL subframe is divided into a control regionand a data region in the time domain. The control region includes up tofirst three (optionally, up to four) OFDM symbols of a 1^(st) slot inthe subframe. However, the number of OFDM symbols included in thecontrol region may vary. A physical downlink control channel (PDCCH) isallocated to the control region, and a physical downlink shared channel(PDSCH) is allocated to the data region.

As disclosed in 3GPP TS 36.211 V8.7.0, the 3GPP LTE classifies aphysical channel into a data channel and a control channel. Examples ofthe data channel include a physical downlink shared channel (PDSCH) anda physical uplink shared channel (PUSCH). Examples of the controlchannel include a physical downlink control channel (PDCCH), a physicalcontrol format indicator channel (PCFICH), a physical hybrid-ARQindicator channel (PHICH), and a physical uplink control channel(PUCCH).

A physical control format indicator channel (PCFICH) transmitted in a1^(st) OFDM symbol of the subframe carries a control format indicator(CFI) regarding the number of OFDM symbols (i.e., a size of the controlregion) used for transmission of control channels in the subframe. TheUE first receives the CFI on the PCFICH, and thereafter monitors thePDCCH. Unlike the PDCCH, the PCFICH does not use blind decoding, and istransmitted by using a fixed PCFICH resource of the subframe.

A physical hybrid-ARQ indicator channel (PHICH) carries apositive-acknowledgement (ACK)/negative-acknowledgement (NACK) signalfor an uplink hybrid automatic repeat request (HARQ). The ACK/NACKsignal for UL data on a PUSCH transmitted by the UE is transmitted onthe PHICH.

A physical broadcast channel (PBCH) is transmitted in first four OFDMsymbols in a 2^(nd) slot of a 1^(st) subframe of a radio frame. The PBCHcarries system information necessary for communication between the UEand a BS. The system information transmitted through the PBCH isreferred to as a master information block (MIB). In comparison thereto,system information transmitted on the PDCCH is referred to as a systeminformation block (SIB).

Control information transmitted through the PDCCH is referred to asdownlink control information (DCI). The DCI may include resourceallocation of the PDSCH (this is referred to as a DL grant), resourceallocation of a PUSCH (this is referred to as a UL grant), a set oftransmit power control commands for individual UEs in any UE group,and/or activation of a voice over Internet protocol (VoIP).

DCI formats transmitted on a PDCCH are described.

1. A DCI format 0 is used for PUSCH scheduling. 2. A DCI format 1 isused for one PDSCH codeword scheduling. 3. A DCI format 1A is used forcompact scheduling of one PDSCH codeword or a random access process. 4.A DCI format 1B includes precoding information and is used for compactscheduling for one PDSCH codeword. 5. A DCI format 1C is used for verycompact scheduling for one PDSCH codeword. 6. A DCI format 1D includesprecoding and power offset information and is used for compactscheduling for one PDSCH codeword. 7. A DCI format 2 is used todesignate a PDSCH for a close-loop MIMO operation. 8. A DCI format 2A isused to designate a PDSCH for an open-loop MIMO operation. 9. A DCIformat 3 is used to transmit a transmit power control (TPC) command fora PUCCH and a PUSCH through 2-bit power regulation. A plurality of TPCcommands may be included in the DCI format 3. 10. A DCI format 3A isused to transmit a TPC command for a PUCCH and a PUSCH through 1-bitpower regulation. A plurality of TPC commands may be included in the DCIformat 3A.

FIG. 5 shows a structure of a UL subframe.

Referring to FIG. 5, the UL subframe may be divided into a controlregion and a data region in a frequency domain. The control region is aregion to which a physical uplink control channel (PUCCH) carrying ULcontrol information is allocated. The data region is a region to which aphysical uplink shared channel (PUSCH) carrying user data is allocated.

The PUCCH is allocated in an RB pair in a subframe. RBs belonging to theRB pair occupy different subcarriers in each of a 1^(st) slot and a2^(nd) slot. The RB pair has the same RB index m.

Meanwhile, the PUCCH supports multiple formats. A PUCCH having adifferent number of bits per subframe may be used according to amodulation scheme which is dependent on the PUCCH format.

Table 3 below shows an example of a modulation scheme and the number ofbits per subframe according to the PUCCH format.

TABLE 3 PUCCH Modulation Number of bits format scheme per subframe 1 N/A N/A 1a BPSK 1 1b QPSK 2 2  QPSK 20 2a QPSK + BPSK 21 2b QPSK + QPSK22

The PUCCH format 1 is used for transmission of a scheduling request(SR). The PUCCH formats 1a/1b are used for transmission of an ACK/NACKsignal. The PUCCH format 2 is used for transmission of a CQI. The PUCCHformats 2a/2b are used for simultaneous transmission of the CQI and theACK/NACK signal. When only the ACK/NACK signal is transmitted in asubframe, the PUCCH formats 1a/1b are used. When the SR is transmittedalone, the PUCCH format 1 is used. When the SR and the ACK/NACK aresimultaneously transmitted, the PUCCH format 1 is used, and in thiscase, the ACK/NACK signal is modulated by using a resource allocated tothe SR.

All PUCCH formats use a cyclic shift (CS) of a sequence in each OFDMsymbol. The cyclically shifted sequence is generated by cyclicallyshifting a base sequence by a specific CS amount. The specific CS amountis indicated by a CS index.

An example of a base sequence r_(u)(n) is defined by the followingequation.r _(u)(n)=e ^(jb(n)π/4)  [Equation 1]

Herein, u denotes a root index, and n denotes a component index in therange of 0≤n≤N−1, where N is a length of the base sequence. b(n) isdefined in the section 5.5 of 3GPP TS 36.211 V8.7.0.

A length of a sequence is equal to the number of elements included inthe sequence. u can be determined by a cell identifier (ID), a slotnumber in a radio frame, etc. When it is assumed that the base sequenceis mapped to one RB in a frequency domain, the length N of the basesequence is 12 since one RB includes 12 subcarriers. A different basesequence is defined according to a different root index.

The base sequence r(n) can be cyclically shifted by Equation 2 below togenerate a cyclically shifted sequence r(n, I_(cs)).

$\begin{matrix}{{{r\left( {n,I_{cs}} \right)} = {{r(n)} \cdot {\exp\left( \frac{j\; 2\;\pi\; I_{cs}n}{N} \right)}}},{0 \leq I_{cs} \leq {N - 1}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Herein, I_(cs) denotes a CS index indicating a CS amount (0≤I_(cs)≤N−1).

Hereinafter, the available CS of the base sequence denotes a CS indexthat can be derived from the base sequence according to a CS interval.For example, if the base sequence has a length of 12 and the CS intervalis 1, the total number of available CS indices of the base sequence is12. Alternatively, if the base sequence has a length of 12 and the CSinterval is 2, the total number of available CS indices of the basesequence is 6.

FIG. 6 shows a channel structure of a PUCCH format 1b in a normal CPcase.

One slot includes 7 OFDM symbols. Three OFDM symbols are referencesignal (RS) OFDM symbols for an RS. Four OFDM symbols are data symbolsfor an ACK/NACK signal.

In the PUCCH format 1b, a modulation symbol d(0) is generated bymodulating a 2-bit ACK/NACK signal based on quadrature phase shiftkeying (QPSK).

A CS index I_(cs) may vary depending on a slot number n_(s) in a radioframe and/or a symbol index 1 in a slot.

In the normal CP case, there are four data OFDM symbols for transmissionof an ACK/NACK signal in one slot. Therefore, assume that CS indicescorresponding to the respective data OFDM symbols are denoted byI_(cs0), I_(cs1), I_(cs2), and I_(cs3).

The modulation symbol d(0) is spread to a cyclically shifted sequencer(n,I_(cs)). When a one-dimensional spreading sequence corresponding toan (i+1)^(th) OFDM symbol in a subframe is denoted by m(i), it can beexpressed as follows.

{m(0), m(1), m(2), m(3)}={d(0)r(n,I_(cs0)), d(0)r(n,I_(cs1)),d(0)r(n,I_(cs2)), d(0)r(n,I_(cs3))}

In order to increase UE capacity, the one-dimensional spreading sequencecan be spread by using an orthogonal sequence. An orthogonal sequencew_(i)(k) (where i is a sequence index, 0≤k≤K−1) having a spread factorK=4 uses the following sequence.

TABLE 4 Index (i) [w_(i)(0), w_(i)(1), w_(i)(2), w_(i)(3)] 0 [+1, +1,+1, +1] 1 [+1, −1, +1, −1] 2 [+1, −1, −1, +1]

An orthogonal sequence w_(i)(k) (where i is a sequence index, 0≤k≤K−1)having a spread factor K=3 uses the following sequence.

TABLE 5 Index (i) [w_(i)(0), w_(i)(1), w_(i)(2)] 0 [+1, +1, +1] 1 [+1,e^(j2π/3), e^(j4π/3)] 2 [+1, e^(j4π/3), e^(j2π/3)]

A different spread factor can be used for each slot.

Therefore, when any orthogonal sequence index i is given,two-dimensional spreading sequences {s(0), s(1), s(2), s(3)} can beexpressed as follows.

-   -   {s(0), s(1), s(2), s(3)}={w_(i)(0)m(0), w_(i)(1)m(1),        w_(i)(2)m(2), w_(i)(3)m(3)}

The two-dimensional spreading sequences {s(0), s(1), s(2), s(3)} aresubjected to inverse fast Fourier transform (IFFT) and thereafter aretransmitted in corresponding OFDM symbols. Accordingly, an ACK/NACKsignal is transmitted on a PUCCH.

A reference signal of the PUCCH format 1b is also transmitted bycyclically shifting the base sequence r(n) and then by spreading it bythe use of an orthogonal sequence. When CS indices corresponding tothree RS OFDM symbols are denoted by I_(cs4), I_(cs5), and I_(s6), threecyclically shifted sequences r(n,I_(cs4)), r(n,I_(cs5)), andr(n,I_(cs6)) can be obtained. The three cyclically shifted sequences arespread by the use of an orthogonal sequence w^(RS) _(i)(k) having aspreading factor K=3.

An orthogonal sequence index i, a CS index I_(cs), and a resource blockindex m are parameters required to construct the PUCCH, and are alsoresources used to identify the PUCCH (or UE). If the number of availablecyclic shifts is 12 and the number of available orthogonal sequenceindices is 3, PUCCHs for 36 UEs in total can be multiplexed to oneresource block.

In the 3GPP LTE, a resource index n⁽¹⁾ _(PUCCH) is defined in order forthe UE to obtain the three parameters for constructing the PUCCH. Theresource index n⁽¹⁾ _(PUCCH) is defined to n_(CCE)+N⁽¹⁾ _(PUCCH), wheren_(CCE) is an index of a first CCE used for transmission of acorresponding DCI (i.e., a DL resource allocation used to receive DLdata corresponding to an ACK/NACK signal), and N⁽¹⁾ _(PUCCH) is aparameter reported by a BS to the UE by using a higher-layer message.

Time, frequency, and code resources used for transmission of theACK/NACK signal are referred to as ACK/NACK resources or PUCCHresources. As described above, an index of a PUCCH resource or theACK/NACK resource required to transmit the ACK/NACK signal on the PUCCHcan be expressed with at least any one of an orthogonal sequence indexi, a CS index I_(cs), a resource block index m, and a PUCCH index n⁽¹⁾_(PUCCH) for obtaining the three indices. The ACK/NACK resource mayinclude at least any one of an orthogonal sequence, a cyclic shift, aresource block, and a combination thereof.

FIG. 7 shows a channel structure of PUCCH formats 2/2a/2b in a normal CPcase.

Referring to FIG. 7, in the normal CP case, OFDM symbols 1 and 5 (i.e.,2^(nd) and 6^(th) OFDM symbols) are used for a demodulation referencesignal (DM RS) which is an uplink reference signal, and the remainingOFDM symbols are used for CQI transmission. In an extended CP case, anOFDM symbol 3 (i.e., a 4^(th) OFDM symbol) is used for a DM RS.

10 CQI information bits are channel coded, for example, with a codingrate of ½, to generate 20 coded bits. A Reed-Muller code can be used inthe channel coding. After scheduling, QPSK constellation mapping isperformed to generate QPSK modulation symbols (e.g., d(0) to d(4) in aslot 0). Each QPSK modulation symbol is subjected to IFFT after beingmodulated by using a cyclic shift of a base RS sequence having a lengthof 12, and is then transmitted in each of 10 SC-FDMA symbols in asubframe. 12 equally-spaced cyclic shifts allow 12 different UEs to beorthogonally multiplexed on the same PUCCH RB. A DM RS sequence appliedto the ODMA symbols 1 and 5 may be the base RS sequence having thelength of 12.

Meanwhile, in a carrier aggregation system or a TDD system, an amount ofACK/NACK to be transmitted in one uplink subframe may be greater than orequal to 2 bits. In this case, a PUCCH format 3 may be used.

FIG. 8 shows an example of a PUCCH format 3 based on block spreading.

Referring to FIG. 8, the PUCCH format 3 is a PUCCH format which uses ablock spreading method. The block spreading method is a method ofmultiplexing a modulation symbol sequence modulated from multi-bitACK/NACK by using a block spreading code. That is, the PUCCH format 3 isused when a symbol sequence (e.g., an ACK/NACK symbol sequence) istransmitted in a spreading manner in a time domain by the use of theblock spreading code. An orthogonal cover code (OCC) may be used as theblock spreading code. Control signals of several UEs may be multiplexedby the block spreading code. In the PUCCH format 2, one symbol sequenceis transmitted in an overlapping manner in the time domain, and UEmultiplexing is performed using cyclic shift of a constant amplitudezero auto-correlation (CAZAC) sequence, whereas in the PUCCH format 3, asymbol sequence (indicated by {d1, d2,}) consisting of one or moresymbols is transmitted across a frequency domain of each data symbol(i.e., a symbol indicated by Data), and UE multiplexing is performed byspreading it in the time domain by the use of a block spreading code(indicated by C1, C2, C3, C4, C5). Although a case where two RS symbols(i.e., symbols indicated by RS) are used in one slot is shown in FIG. 8,the present invention is not limited thereto, and thus an OCC having aspreading factor of 4 may be used. An RS symbol may be generated from aCAZAC sequence having a specific cyclic shift, and may be transmitted ina format in which a specific OCC is multiplied by a plurality of RSsymbols of the time domain.

Now, ACK/NACK transmission for HARQ in 3GPP LTE time division duplex(TDD) is described.

As described in a TDD frame, a DL subframe and a UL subframe coexist inthe TDD frame. In general, the number of UL subframes is less than thenumber of DL subframes. Therefore, in preparation for a case where theUL subframes for transmitting an ACK/NACK signal are insufficient, it issupported that a plurality of ACK/NACK signals for a plurality of DLtransport blocks received in a plurality of DL subframes are transmittedin one UL subframe.

According to the section 10.1 of 3GPP TS 36.213 V8.7.0 (2009-05), twoACK/NACK modes, i.e., ACK/NACK bundling and ACK/NACK multiplexing, areintroduced.

The ACK/NACK bundling is an operation in which, if all of PDSCHs (i.e.,DL transport blocks) received by a UE are successfully decoded, ACK istransmitted, and otherwise NACK is transmitted. For this, ACK or NACKfor each PDSCH is compressed using an AND operation (i.e., a logical ANDoperation).

ACK/NACK multiplexing is also called ACK/NACK channel selection (orsimply channel selection). When the ACK/NACK multiplexing is used, theUE transmits ACK/NACK by selecting one PUCCH resource among a pluralityof PUCCH resources.

The following table shows a DL subframe n-k associated with a ULsubframe n depending on the UL-DL configuration in 3GPP LTE. Herein,k∈K, and M is the number of elements of a set K.

TABLE 6 UL-DL Subframe n Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 —— 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4, 6— — 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 — —— — — — 5 — — 13, 12, 9, 8, — — — — — — — 7, 5, 4, 11, 6 6 — — 7 7 5 — —7 7 —

Assume that M DL subframes are associated with a UL subframe n, whereM=3 for example. Since 3 PDCCHs can be received from 3 DL subframes, theUE can acquire 3 PUCCH resources n⁽¹⁾ _(PUCCH,0), n⁽¹⁾ _(PUCCH,1), n⁽¹⁾_(PUCCH,2), n⁽¹⁾ _(PUCCH,3). In this case, an example of ACK/NACKchannel selection is shown in the following table.

TABLE 7 HARQ-ACK(0), HARQ-ACK(1), HARQ-ACK(2) n⁽¹⁾ _(PUCCH) b(0), b(1)ACK, ACK, ACK n⁽¹⁾ _(PUCCH, 2) 1, 1 ACK, ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 1)1, 1 ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH, 0) 1, 1 ACK, NACK/DTX, NACK/DTXn⁽¹⁾ _(PUCCH, 0) 0, 1 NACK/DTX, ACK, ACK n⁽¹⁾ _(PUCCH, 2) 1, 0 NACK/DTX,ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 1) 0, 0 NACK/DTX, NACK/DTX, ACK n⁽¹⁾_(PUCCH, 2) 0, 0 DTX, DTX, NACK n⁽¹⁾ _(PUCCH, 2) 0, 1 DTX, NACK,NACK/DTX n⁽¹⁾ _(PUCCH, 1) 1, 0 NACK, NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH, 0)1, 0 DTX, DTX, DTX N/A N/A

In the above table, HARQ-ACK(i) denotes ACK/NACK for an i^(th) DLsubframe among the M DL subframes. Discontinuous transmission (DTX)implies that a DL transport block cannot be received on a PDSCH in acorresponding DL subframe or a corresponding PDCCH cannot be detected.In Table 7 above, there are three PUCCH resources n⁽¹⁾ _(PUCCH,0), n⁽¹⁾_(PUCCH,1), and n⁽¹⁾ _(PUCCH,2), and b(0) and b(1) are 2 bitstransmitted by using a selected PUCCH.

For example, if the UE successfully receives three DL transport blocksin three DL subframes, the UE transmits bits (1,1) through the PUCCH byperforming QPSK modulation using n⁽¹⁾ _(PUCCH,2). If the UE fails todecode the DL transport block and successfully decodes the remainingtransport blocks in a 1^(st) (i=0) DL subframe, the UE transmits bits(0, 1) through the PUCCH using n⁽¹⁾ _(PUCCH,2). That is, theconventional PUCCH format 1b can transmit only 2-bit ACK/NACK. However,channel selection is used to express more ACK/NACK states, by linkingthe allocated PUCCH resources and an actual ACK/NACK signal.

In ACK/NACK channel selection, NACK and DTX are coupled if at least oneACK exists. This is because a combination of a reserved PUCCH resourceand a QPSK symbol is not enough to express all ACK/NACK states. However,if the ACK does not exist, the DTX and the NACK are decoupled.

In the aforementioned ACK/NACK bundling or channel selection, the totalnumber of PDSCHs for which ACK/NACK is transmitted by the UE isimportant. If the UE fails to receive some of the plurality of PDCCHsfor scheduling a plurality of PDSCHs, an error occurs in the totalnumber of PDSCHs for which the ACK/NACK is transmitted, and thusACK/NACK may be transmitted erroneously. To correct this error, a TDDsystem transmits the PDCCH by including a downlink assignment index(DAD. The DAI reports a counting value by counting the number of PDCCHsfor scheduling the PDSCHs.

The aforementioned ACK/NACK bundling and ACK/NACK multiplexing may beapplied when one serving cell is configured for the UE in TDD.

For example, it is assumed that one serving cell is configured (i.e.,only a primary cell is configured) to the UE in TDD, ACK/NACK bundlingor ACK/NACK multiplexing is used, and M=1. That is, it is assumed a casewhere one DL subframe is associated with one UL subframe.

1) In a case where the UE detects a PDSCH indicated by a correspondingPDCCH or a semi-persistent scheduling (SPS) release PDCCH in a subframen-k of the primary cell, ACK/NACK is transmitted in a subframe n. InLTE, a BS may report to the UE about at which subframes semi-persistenttransmission/reception is performed, by using a higher layer signal suchas radio resource control (RRC). For example, a parameter given by thehigher layer signal may be a subframe period and an offer value. The UErecognizes semi-persistent transmission through RRC signaling, andthereafter upon receiving an activation/release signal of SPStransmission through a PDCCH, performs or releases SPS PDSCH receptionor SPS PUSCH transmission. That is, even if the UE is subjected to SPSscheduling through RRC signaling, if SPS transmission/reception is notimmediately performed but an activation or release signal is receivedthrough a PDCCH, the SPS transmission/reception is performed in asubframe corresponding to a subframe period and an offset valueallocated through RRC signaling by applying a frequency resource (i.e.,a resource block) based on resource allocation designated in the PDCCHand a modulation and coding rate based on MCS information. In this case,a PDCCH for releasing SPS is called an SPS release PDCCH. In an LTEsystem, a DL SPS release PDCCH requires ACK/NACK signal transmission.

In this case, the UE transmits ACK/NACK in the subframe n by using thePUCCH formats 1a/1b based on the PUCCH resource n^((1,p)) _(PUCCH). Inn^((1,P)) _(PUCCH), p indicates that it belongs to an antenna port p. kis determined by Table 6 above.

The PUCCH resource n^((1,p)) _(PUCCH) may be allocated as follows. p maybe p0 or p1.n ^((1,p=p0)) _(PUCCH)=(M−m−1)·N _(c) +m·N _(c+1) +n _(CCE) +N ⁽¹⁾_(PUCCH) for antenna port p=p0n ^((1,p−p1)) _(PUCCH)=(M−m−1)·N _(c) +m·N _(c+1)+(n _(CCE)+1)+N ⁽¹⁾_(PUCCH) for antenna port p=p1  [Equation 3]

In Equation 3, c is selected from {0,1,2,3} to satisfyN_(c)≤n_(CCE)<N_(c+1) (antenna port p0), N_(c)≤(n_(CCE)+1)<N_(c+1)(antenna port p1). N⁽¹⁾ _(PUCCH) is a value determined by a higher layersignal. N_(C) may be set to N_(C)=max{0, floor [N^(DL) _(RB)·(N^(RB)_(sc)·c−4)/36]}. N^(DL) _(RB) is a DL bandwidth. N^(RB) _(sc) is a sizein a frequency domain of a resource block, and is indicated by thenumber of subcarriers. n_(CCE) is a first CCE number used intransmission of a corresponding PDCCH in a subframe n-k_(m). m is avalue which allows k_(m) to be a smallest value in the set K of Table 6above.

2) If the UE detects an SPS PDSCH, that is, a PDSCH not having acorresponding PDCCH, in a DL subframe n-k of the primary cell, thenACK/NACK can be transmitted in a subframe n by using a PUCCH resourcen^((1,p)) _(PUCCH) as described below.

Since the SPS PDSCH does not have a PDCCH for scheduling, the UEtransmits ACK/NACK through the PUCCH formats 1a/1b based on n^((1,p))_(PUCCH) determined by a higher layer signal. For example, fourresources (i.e., a 1^(st) PUCCH resource, a 2^(nd) PUCCH resource, a3^(rd) PUCCH resource, and a 4^(th) PUCCH resource) can be reserved byusing an RRC signal, and one resource can be indicated by using atransmission power control (TPC) field of a PDCCH for activating SPSscheduling.

The following table shows an example of indicating a resource forchannel selection according to the TPC field value.

TABLE 8 TPC field value Resource for channel selection ‘00’ 1^(st) PUCCHresource ‘01’ 2^(nd) PUCCH resource ‘10’ 3^(rd) PUCCH resource ‘11’4^(th) PUCCH resource

For another example, it is assumed that one serving cell is configured(that is, only a primary cell is configured) for the UE in TDD, ACK/NACKmultiplexing is used, and M>1. That is, it is assumed that a pluralityof DL subframes is associated with one UL subframe.

1) If the UE receives a PDSCH in a subframe n-k_(i) (0≤i≤M−1) or detectsa DL SPS release PDCCH, a PUCCH resource n⁽¹⁾ _(PUCCH,i) fortransmitting ACK/NACK may be allocated by the following equation.Herein, k_(i)∈K, and the set K is described above with reference toTable 6.n ⁽¹⁾ _(PUCCH,i)=(M−i−1)·N _(c) +i·N _(c+1) +n _(CCE,i) +N ⁽¹⁾_(PUCCH)  [Equation 4]

Herein, c is selected from {0,1,2,3} to satisfy N_(c)≤n_(CCE,m)≤N_(c+1).N⁽¹⁾ _(PUCCH) is a value determined by using a higher layer signal.N_(C) may be max{0, floor [N^(DL) _(RB)·(N^(RB) _(sc)·c−4)/36]}. N^(DL)_(RB) is a downlink bandwidth, and N^(RB) _(sc) is a size of a resourceblock indicated with the number of subcarriers in the frequency domain.n_(CCE,m) is a 1^(st) CCE number used in transmission of a correspondingPDCCH at a subframe n-k_(m).

2) If the UE receives a PDSCH not having a corresponding PDCCH (i.e., anSPS PDSCH) in the subframe n-k_(i), n⁽¹⁾ _(PUCCH,i) is determinedaccording to a configuration given by a higher layer signal andaccording to Table 8.

If two or more serving cells are configured for the UE in TDD, the UEtransmits ACK/NACK by using channel selection based on the PUCCH format1b or by using the PUCCH format 3.

For example, in a case where a plurality of serving cells which usechannel selection based on the PUCCH format 1b are configured, if anACK/NACK bit is greater than 4 bits, the UE performs spatial ACK/NACKbundling for a plurality of codewords in one DL subframe, and transmitsthe bundled ACK/NACK bit for each serving cell through the channelselection based on the PUCCH format 1b. The spatial ACK/NACK bundlingimplies that ACK/NACK for each codeword is compressed through a logicalAND operation in the same DL subframe.

If the ACK/NACK bit is less than or equal to 4 bits, the spatialACK/NACK bundling is not used, and transmission is performed through thechannel selection based on the PUCCH format 1b.

For another example, in a case where two or more serving cells using thePUCCH format 3 are configured for the UE, if the ACK/NACK bit is greaterthan 20 bits, the spatial ACK/NACK bundling is performed in each servingcell, and the ACK/NACK bit which is subjected to the spatial ACK/NACKbundling may be transmitted using the PUCCH format 3. If the ACK/NACKbit is less than or equal to 20 bits, the spatial ACK/NACK bundling isnot used, and the ACK/NACK bit is transmitted using the PUCCH format 3.

Now, a carrier aggregation system will be described. The carrieraggregation system is also called a multiple carrier system.

A 3GPP LTE system supports a case where a DL bandwidth and a ULbandwidth are differently configured under the premise that onecomponent carrier (CC) is used. The 3GPP LTE system supports up to 20MHz, and the UL bandwidth and the DL bandwidth may be different fromeach other. However, only one CC is supported in each of UL and DLcases.

Spectrum aggregation (also referred to as bandwidth aggregation orcarrier aggregation) supports a plurality of CCs. For example, if 5 CCsare assigned as a granularity of a carrier unit having a bandwidth of 20MHz, a bandwidth of up to 100 MHz can be supported.

One DL CC or a pair of a UL CC and a DL CC can correspond to one cell.Therefore, when a UE communicates with a BS through a plurality of DLCCs, it can be said that the UE receives a service from a plurality ofserving cells.

FIG. 9 shows an example of comparing a single carrier system and acarrier aggregation system.

Although the carrier aggregation system (see FIG. 9(b)) has three DL CCsand three UL CCs, the number of DL CCs and the number of UL CCs are notlimited thereto. A PDCCH and a PDSCH may be independently transmitted ineach DL CC. A PUCCH and a PUSCH may be independently transmitted in eachUL CC. Alternatively, the PUCCH may be transmitted only through aspecific UL CC.

Since three DL CC-UL CC pairs are defined, it can be said that a UEreceives a service from three serving cells.

The UE may monitor the PDCCH in a plurality of DL CCs, and may receive aDL transport block simultaneously via the plurality of DL CCs. The UEmay transmit a plurality of UL transport blocks simultaneously via aplurality of UL CCs.

A pair of a DL CC #1 and a UL CC #1 may be a 1^(st) serving cell, a pairof a DL CC #2 and a UL CC #2 may be a 2^(nd) serving cell, and a DL CC#3 may be a 3^(rd) serving cell. Each serving cell may be identified byusing a cell index (CI). The CI may be cell-specific or UE-specific.

The serving cell may be classified into a primary cell and a secondarycell. The primary cell is a cell designated as the primary cell when theUE performs an initial network entry process or starts a networkre-entry process or performs a handover process. The primary cell isalso called a reference cell. The secondary cell may be configured afteran RRC connection is established, and may be used to provide anadditional radio resource. At least one primary cell is configuredalways. The secondary cell may be added/modified/released by usinghigher-layer signaling (e.g., RRC messages). The CI of the primary cellmay be fixed. For example, a lowest CI may be designated as a CI of theprimary cell.

The carrier aggregation system may support cross-carrier scheduling. Thecross-carrier scheduling is a scheduling method capable of performingresource allocation of a PDSCH transmitted by using a different CCthrough a PDCCH transmitted via a specific CC and/or resource allocationof a PUSCH transmitted via another CC other than a CC basically linkedto the specific CC. That is, the PDCCH and the PDSCH may be transmittedthrough different DL CCs, and the PUSCH may be transmitted through adifferent UL CC other than a UL CC basically linked to a DL CC on whicha PDCCH including a UL grant is transmitted. As such, in a systemsupporting the cross-carrier scheduling, a carrier indicator is requiredto report a specific DL CC/UL CC used to transmit the PDSCH/PUSCH forwhich the PDCCH provides control information. A field including thecarrier indicator is hereinafter called a carrier indication field(CIF). Hereinafter, a scheduling carrier or a scheduling cell implies acarrier or serving cell for transmitting a UL grant or a DL grant, and ascheduled carrier or a scheduled cell implies a carrier or serving cellfor receiving or transmitting a data channel by using the UL grant orthe DL grant.

Non-cross carrier scheduling is a scheduling method extended from theconventional scheduling method. That is, it is a scheduling method inwhich a PDSCH and a PDCCH for scheduling the PDSCH are transmitted inthe same DL CC. In addition, it is a scheduling method in which a PDCCHfor scheduling a PUSCH is transmitted in a DL CC and a PUSCH istransmitted in a UL CC basically linked to the DL CC.

Now, the present invention is described.

Machine type communication (MTC), multi-user multi-input multi-output(MU-MIMO), and carrier aggregation between TDD cells using differentUL-DL configurations, aggregation between cells having different framestructures (e.g., a TDD frame and an FDD frame), aggregation between alegacy carrier and a new carrier type (NCT), aggregation between a macrocell and a small cell, etc., may be used in a next generation wirelesscommunication system. Further, the number of simultaneously scheduledUEs may be increased.

Although aggregation may be achieved between cells provided by the sameBS existing at a specific location in such a system, aggregation mayalso be achieved between cells provided by different BSs existing atdifferent locations. In the latter case, scheduling for each BS may beperformed due to a control information delay between the BSs.

In addition, unlike the conventional system in which transmission of aPUCCH as an uplink control channel is limited only to a primary cell, afuture system can transmit the PUCCH not only in the primary cell butalso in a secondary cell. In this case, the secondary cell capable oftransmitting the PUCCH may be designated such that only one cell isallowed for each cell group, or may be specified through signaling. Thecell group may be determined according to a predetermined rule. The rulemay be determined according to a delay time between BSs. Cells capableof ignoring the delay time may be determined as the same cell group, andcells which need to consider the delay time may be determined asdifferent cell groups. Alternatively, the cell group may be determinedexplicitly through an RRC message.

Hereinafter, for a case where the transmission of the PUCCH is alsoallowed in the secondary cell without being limited to the primary cell,a method of controlling transmission power of each channel (e.g., PUCCH,PUSCH) and how to perform other various configurations, etc., will bedescribed hereinafter.

<PUCCH Power Control>

In the conventional wireless communication system, a PUCCH istransmitted only on a primary cell. Therefore, transmission powercontrol of the PUCCH is defined mainly based on the primary cell.However, in a future wireless communication system, PUCCH transmissionmay also be possible in a secondary cell in addition to the primarycell. In particular, if the primary cell is a macro cell and thesecondary cell is a small cell, an optimal transmission power amount andcharacteristic may vary for each cell. Herein, the macro cell may be thelegacy BS, and may be a device which uses higher power than the smallcell. The small cell may be a low-power device which is arrangedinside/outside a coverage of the legacy BS. In this case, how tocontrol/determine the PUCCH transmission power is a matter to beconsidered.

FIG. 10 shows a PUCCH power control method according to an embodiment ofthe present invention.

A UE receives from a BS a first parameter set and a second parameter setwhich are used to determine PUCCH transmission power (step S310). Thefirst parameter set may be a set of parameters used to determine thePUCCH transmission power when a PUCCH is transmitted through only aprimary cell. The second parameter set may be a set of parameters usedto determine the PUCCH transmission power when the PUCCH is transmittedonly through a secondary cell. The secondary parameter set may be a setof parameters for determining the PUCCH transmission power when thePUCCH is transmitted through both of the primary cell and the secondarycell. Parameters included in the second parameter set may be the same asor a part of parameters of the first parameter set, and optionally mayinclude additional parameters not included in the first parameter set.

The UE determines the PUCCH transmission power by using the firstparameter set or the second parameter set according to a cell in whichthe PUCCH is transmitted (step S320).

For example, if the PUCCH is transmitted only in the primary cell, thePUCCH transmission power is determined by using the first parameter set.If the PUCCH can be transmitted in both of the primary cell and thesecondary cell, the UE may use the first parameter set to determinePUCCH transmission power transmitted in the primary cell and the secondparameter set to determine PUCCH transmission power transmitted in thesecondary cell. Alternatively, if the PUCCH can be transmitted in bothof the primary cell and the secondary cell, the PUCCH transmission powerof both of the primary cell and the secondary cell may be determined byusing the second parameter set.

Now, the PUCCH power control method described with reference to FIG. 10is described in greater detail.

First, a method of determining transmission power of the PUCCH isdescribed when the PUCCH is transmitted only in the primary cell. If thetransmission power of the PUCCH transmitted in a subframe i is denotedby P_(PUCCH)(i), P_(PUCCH)(i) may be determined as follows.

$\begin{matrix}{{P_{PUCCH}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0\;\_\;{PUCCH}} + {PL}_{c} + {h\left( {n_{CQI},{n_{{HARQ},}n_{SR}}} \right)} +} \\{{\Delta_{F\;\_\;{PUCCH}}(F)} + {\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

As shown in Equation 5 above, various parameters are required todetermine the PUCCH transmission power. If the PUCCH is transmitted onlyin the primary cell, the parameters required to determine the PUCCHtransmission power may be called a first parameter set.

In Equation 5 above, _(PCMAX)(i) is maximum transmission power assignedto a UE at a subframe i of a serving cell c, and is determined by the UEon the basis of a parameter received from a BS or a UE-specificparameter.

Δ_(F) _(_) _(PUCCH)(F) is provided by a higher layer, and a value ofΔ_(F) _(_) _(PUCCH)(F) corresponds to a PUCCH format (F). Δ_(T×D)(F) isa value given by the higher layer when the UE is configured to transmitthe PUCCH through two antenna ports by the higher layer. Δ_(T×D)(F′)plays a role of providing a power offset value for each PUCCH formatwhen a T×D is used in PUCCH transmission.

P_(O) _(_) _(PUCCH) is a value given by the higher layer, and g(i) is acurrent PUCCH power control adjustment state. PL_(c) is a value for apath loss.

h(n_(CQI), n_(HARQ), n_(SR)) is a value depending on a PUCCH format.n_(CQI) corresponds to the number of CQI information bits. n_(SR) is 1if SR is set in a subframe i, and otherwise 0. If two or more servingcells are configured for the UE, or one serving cell is configured andis transmitted using a PUCCH format 3, in case of FDD, n_(Q) is thetotal number of SPS release PDCCHs/EPDCCHs or the number of transportblocks received in a subframe n-4 (when a subframe for transmittingACK/NACK is a subframe n) of each configured cell. In case of TDD, itmay be determined on the basis of the total number of release PDCCHs orthe number of transport blocks received in a subframe n-k correspondingto a subframe n in each configured cell. Alternatively, in case of TDD,it may be determined on the basis of the total number of PDSCHs withouta corresponding PDSCCH/EPDCCH or the number of PDCCHs/EPDCCHs receivedin a subframe n-k corresponding to a subframe n in each configured cell.In other cases, it indicates the number of HARQ bits transmitted in asubframe i.

Meanwhile, if the PUCCH can be transmitted also in the secondary cell,Equation 5 above may be changed as described below by using parametersincluded in the second parameter set. The parameters included in thesecond parameter set may be respective parameters of Equation 5.

In Equation 5, P_(O) _(_) _(PUCCH) is determined by a sum of P_(O) _(_)_(NOMINAL) _(_) _(PUCCH) and P_(O) _(_) _(UE) _(_) _(PUCCH)Herein, apossible case is as follows: 1) regarding the two parameters P_(O) _(_)_(NOMINAL) _(_) _(PUCCH) and P_(O) _(_) _(UE) _(_) _(PUCCH), the samevalue used in the primary cell may also be used in the secondary cell;or 2) P_(O) _(_) _(NOMINAL) _(_) _(PUCCH,c) which is P_(O) _(_)_(NOMINAL) _(_) _(PUCCH) for a cell c may be set for each cell, andP_(O) _(_) _(UE) _(_) _(PUCCH) may be set to a common value for cells(i.e., the primary cell and the secondary cell) configured for the UE;or 3) P_(O) _(_) _(NOMINAL) _(_) _(PUCCH) may be set to a common valuefor all cells configured for the UE, and P_(O) _(_) _(UE) _(_)_(PUCCH,c) may be set for each cell configured for the UE; or 4) both ofP_(O) _(_) _(NOMINAL) _(_) _(PUCCH,c) and P_(O) _(_) _(UE) _(_)_(PUCCH,c) may be set for each cell. In the aforementioned cases 1) to4), a value used for each cell may be commonly set for a specificsecondary cell group or all secondary cells.

If the PUCCH is transmitted only in the primary cell, c=0 in PL_(c). Ifthe PUCCH can be transmitted also in the secondary cell, PL_(c) may be apath loss of a downlink cell matched in a cell-specific manner to anuplink cell of the secondary cell, and a downlink cell may be indicatedby a system information block-2 (SIB-2) or may be predetermined.Alternatively, PL_(c) may be a path loss of a downlink cell matched in aUE-specific manner to an uplink cell of the secondary cell. That is, thepath loss of the downlink cell matched to the uplink cell may beindicated through UE-specific RRC signaling.

If it is configured such that a specific cell includes only an uplinksubframe without a downlink subframe or such that the specific cell isused by a UE by being aggregated only in an uplink, a BS may report aspecific downlink cell to which PL_(c) belongs.

h(n_(CQI), n_(HARQ), n_(SR)) is a parameter determined on the basis ofan information amount of UCI transmitted on a PUCCH. h(n_(CQI),n_(HARQ), n_(SR)) may be determined according to the information amountof UCI transmitted on the PUCCH for each cell. For a cell c, if n_(CQI)is denoted by n_(CQI,c), n_(HARQ) is denoted by n_(HARQ,c), and n_(SR)is denoted by n_(SR,c), then n(n_(CQI,c), n_(HARQ,c), n_(SR,c)) may beprovided in the second parameter set.

Δ_(F) _(_) _(PUCCH)(F) is provided by a higher layer, and a value ofΔ_(F) _(_) _(PUCCH)(F) corresponds to a PUCCH format (F). Δ_(F) _(_)_(PUCCH)(F) may be applied as follows: 1) while maintaining a previousvalue determined for each PUCCH format, a common value may be applied toall cells configured for a UE; or 2) a configuration of a value for eachPUCCH format may vary depending on a cell characteristic. A value usedfor each cell may be commonly set for a specific secondary cell group orfor all secondary cells.

Δ_(T×D)(F′) is a value given by the higher layer when the UE isconfigured to transmit the PUCCH through two antenna ports by the higherlayer. In the conventional method, a PUCCH T×D configuration isdetermined for each PUCCH format. That is, according to Δ_(T×D)(F′)included in the first parameter set, whether to apply a power offset fora T×D is determined for each PUCCH format. Δ_(T×D)(F) included in thesecond parameter set may be configured as follows: 1) the PUCCH T×D iscommonly configured in all cells for each PUCCH format, or 2) the PUCCHT×D is configured separately in each cell for each PUCCH format. The T×Dmay be commonly configured for a specific secondary cell group or allsecondary cells.

g(i) is a value accumulated according to a TPC. g(i) included in thesecond parameter set may be applied as follows. 1) A TPC value may becommonly applied to all cells. That is, a common summation may beachieved. Even if P_(O) _(_) _(UE) _(_) _(PUCCH,c) of a specific cell ischanged, g(0)=0 when it is changed by a higher layer. 2) Alternatively,a TPC value transmitted through a PDCCH for scheduling a downlink cellwhich is a target of UCI transmitted through the PUCCH may be appliedseparately to each cell. That is, a separate summation may be achieved.A value used for each cell may be commonly set for a specific secondarycell group or all secondary cells.

If a value of P_(O) _(_) _(UE) _(_) _(PUCCH) included in the firstparameter set is changed by a higher layer, g(0)=0. In the secondparameter set, a possible case is as follows: 1) if P_(O) _(_) _(UE)_(_) _(PUCCH) is commonly applied to all cells, it may be set tog_(c)(0)=0; or 2) if P_(O) _(_) _(UE) _(_) _(PUCCH) is applied to eachcell, it may be set to g_(c)(0)=0 only for a cell corresponding to thechanged P_(O) _(_) _(UE) _(_) _(PUCCH,c); or 3) if P_(O) _(_) _(UE) _(_)_(PUCCH) is applied to each cell, it may be set to g_(c)(0)=0 not onlyfor a cell corresponding to the changed P_(O) _(_) _(UE) _(_) _(PUCCH,c)but also for all cells; or 4) if P_(O) _(_) _(UE) _(_) _(PUCCH,c) isapplied to each cell, it may be set to g_(c)(0)=0 for all secondarycells or all secondary cell groups when the changed P_(O) _(_) _(UE)_(_) _(PUCCH,c) corresponds to a secondary cell or a specific cellgroup.

Meanwhile, if P_(O) _(_) _(UE) _(_) _(PUCCH) is not changed by thehigher layer in the first parameter set, it may be set tog(0)=ΔP_(rampup)+δ_(msg2). δ_(msg2) is a TPC indicated in a randomaccess response, and ΔP_(rampup) is a total power ramp-up from first tolast preambles provided by the higher layer. In the second parameterset, the following case is possible. 1) ΔP_(rampup,c) may be set foreach cell, and δ_(msg2,c) may also be set for each cell. This may beapplied only to a cell for transmitting a physical random access channel(PRACH), or may be applied to PUCCH transmission cells included in acell group to which the cell for transmitting the PRACH belongs. Anuplink cell which receives a command through a PDCCH to transmit thePRACH for initialization of PUCCH transmission power may be determinedto the PUCCH transmission cell. It may be applied to a primary cell andall of secondary cells, or may be applied limitedly only to a secondarycell group.

2) Alternatively, ΔP_(rampup) may be commonly set for all cells, andδ_(msg2,c) may be set for each cell. In this case, it may be appliedonly to a cell for transmitting a PRACH, or may be applied to PUCCHtransmission cells in a cell group to which the cell for transmittingthe PRACH belongs. 3) Alternatively, ΔP_(rampup,c) may be set for eachcell, and δ_(msg2) may be commonly set for all cells. 4) Alternatively,ΔP_(rampup) may be commonly set for all cells, and δ_(msg2) may alsocommonly set for all cells.

In case of a TPC command, the following method may be used fortransmission. This method may be applied to all cells or to onlysecondary cells other than a primary cell, or may be applied limitedlyto a secondary cell group other than a primary cell group.

1) When aggregating a specific cell, it may be configured such that aTPC is applied in reception using only a DCI format 3/3A. This may belimitedly applied only in PUCCH transmission corresponding to a specificcell group. For example, PUCCH transmission corresponding to the primarycell group may conform to the conventional method, and this may beapplied only to the remaining cell groups other than the primary cellgroup. That is, in case of a PUCCH transmitted in the secondary cell,the TPC may be received with only the DCI format 3/3A.

In this case, all TPC fields may be used as an ARI. Therefore, it ispossible to avoid a situation in which a fallback to an implicit PUCCHformat 1a/1b or an explicit PUCCH format 1a/1b for an SPS response mustbe achieved when the ARI is not present and thus an explicit PUCCHformat 3 resource cannot be selected or an explicit PUCCH format 1bresource for channel selection cannot be selected.

The fallback to the PUCCH format 1a/1b may not be supported. That is,the explicit PUCCH format 3 may be always used as the ARI, or channelselection using the PUCCH format 1b may be always used.

In a case where the PUCCH format 1a/1b fallback is supported, it may beapplied for single scheduling in all cells only when resources can beidentified between cells.

2) A TPC field of all PDCCHs may be used as the TPC. In this case, it isdifficult to transmit an ARI. Therefore, an explicit PUCCH resource isused by allocating one fixed RRC resource without having to use the ARI.

3) Alternatively, the TPC may be used with DAI=1 by designating only onecell for each cell group.

Hereinafter, power control of a PUSCH and an SRS is described when aPUCCH can be transmitted also in a secondary cell.

<PUSCH/SRS Power Control>

In the conventional system, unlike a PUCCH, a PUSCH/SRS can also betransmitted in all activated secondary cells which are aggregated.Therefore, power control is performed for each cell.

1) If only the PUSCH is transmitted without the PUCCH, the power controlmay be performed by the following equation.

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{{10\;{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\;\_\;{PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack\end{matrix}$

2) If the PUCCH and the PUSCH are transmitted simultaneously, the powercontrol may be performed by the following equation.

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min\begin{Bmatrix}{{10\;{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {P_{PUCCH}(i)}} \right)}},} \\\begin{matrix}{{10\;{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\;\_\;{PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

Hereinafter, a method of determining transmission power of a PUSCH isdescribed according to the present invention.

First, if a plurality of PUCCHs are transmitted, the following rule maybe applied.

A remainder obtained by subtracting the total PUCCH transmission powerfrom P_(Cmax) allowed to a UE may be allocated to a PUSCH. Regardingtransmission power between PUSCHs, transmission power of a PUSCH whichtransmits UCI may be first subtracted and thereafter transmission powermay be allocated to a PUSCH which does not transmit the UCI. This isexpressed by the following equation.

$\begin{matrix}{{\sum\limits_{c \in {configuredCell}}{{w(i)}{{\hat{P}}_{{PUSCH},c}(i)}}} < {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c \in {configuredCell}}{{\hat{P}}_{{PUCCH},c}(i)}}}} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

That is, the remaining UE power other than the PUCCH transmission poweris allocated to the PUSCH transmission power.

If a plurality of PUCCHs are transmitted in one cell, the PUSCHtransmission power may be determined by the following equation.

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min\begin{Bmatrix}{{10\;{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {\sum\limits_{c \in {configuredCell}}{{\hat{P}}_{{PUCCH},c}(i)}}} \right)}},} \\\begin{matrix}{{10\;{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\;\_\;{PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

FIG. 11 shows an example of a method of determining PUSCH transmissionpower when a PUCCH can be transmitted also in a secondary cell.

Referring to FIG. 11, a UE allocates transmission power in a primarycell in order of 1) PUCCH and 2) PUSCH (step S410). Thereafter, the UEallocates transmission power in the secondary cell in order of 1) PUCCHand 2) PUSCH.

In the primary cell or a primary cell group, transmission power may beallocated in order of a PUCCH, a PUSCH for transmitting UCI, and otherPUSCHs. Thereafter, in the remaining secondary cells or a secondary cellgroup, transmission power may be allocated in order of a PUCCH and aPUSCH.

If a group index capable of identifying a cell group is allocated, alowest group index may be allocated to the primary cell group, and nextgroup indices may be allocated to the secondary cell group. In thiscase, transmission power may be first allocated to a cell group havingthe lowest group index, and thereafter transmission power may beallocated in sequence to a cell group having a high group index. Theconventional transmission power allocation method may be applied betweencells included in one group.

In addition, cell parameters such as P_(O) _(_) _(PUSCH,c)(j), α_(C)(j),etc., applied to each cell may be commonly applied to a cell group. Theparameters may be commonly set for a specific secondary cell group orfor all secondary cells.

P_(O) _(_) _(PUSCH,C)(j) is determined by a sum of P_(O) _(_) _(NOMINAL)_(_) _(PUSCH,c)(j) and P_(O) _(_) _(UE) _(_) _(PUSCH,c)(j)Conventionally, P_(O) _(_) _(NOMINAL) _(_) _(PUSCH,c)(j) and P_(O) _(_)_(UE) _(_) _(PUSCH,c)(j) are set for each cell. In the presentinvention, as to P_(O) _(_) _(NOMINAL) _(_) _(PUSCH,c)(j) and P_(O) _(_)_(UE) _(_) _(PUSCH,c)(j), a value used for each cell may be commonly setfor a specific secondary cell group or all secondary cells. As to a cellgroup to which the common value is applied, the same value as that usedin the primary cell may be applied.

As to α_(C)(j), a value used for each cell may be commonly set for aspecific secondary cell group or for all secondary cells. As to a cellgroup to which the common value is applied, the same value as that usedin the primary cell may be applied.

The following description is about various configuration changes thatcan be considered by a BS in a system in which a PUCCH can betransmitted also in the secondary cell.

<SRS Configuration>

In the conventional wireless communication system, an SRS configurationis performed for each cell. However, in consideration of a case where asecondary cell is replaced frequently, a method of commonly setting avalue used for each cell may be used for a secondary cell group or allsecondary cells. As to a cell group to which the common value isapplied, the same value as that used in the primary cell may be applied.

<Transmission Mode Configuration>

In the conventional wireless communication system, a transmission mode(TM) is configured separately for each cell. However, in considerationof a case where a secondary cell is replaced frequently, a method ofcommonly setting a value used for each cell may be used for a secondarycell group or all secondary cells. As to a cell group to which thecommon value is applied, the same value as that used in the primary cellmay be applied.

<CSI Reporting Mode Configuration>

In the conventional wireless communication system, a CSI reporting modeis configured separately for each cell. However, in consideration of acase where a secondary cell is replaced frequently, a method of commonlysetting a value used for each cell may be used for a secondary cellgroup or all secondary cells. As to a cell group to which the commonvalue is applied, the same value as that used in the primary cell may beapplied.

<TDD UL/DL Configuration, Special Subframe Configuration>

Conventionally, a TDD UL/DL and a special subframe are configuredseparately for each cell. However, in consideration of a case where asecondary cell is replaced frequently, a method of commonly setting avalue used for each cell may be used for a secondary cell group or allsecondary cells. As to a cell group to which the common value isapplied, the same value as that used in the primary cell may be applied.

<PUCCH Resource Index Offset>

Conventionally, N⁽¹⁾ _(PUCCH) which is a start position of an implicitPUCCH resource index is configured separately for each cell. However, inconsideration of a case where a secondary cell is replaced frequently, amethod of commonly setting a value used for each cell may be used for asecondary cell group or all secondary cells. As to a cell group to whichthe common value is applied, the same value as that used in the primarycell may be applied.

<SRS Configuration>

In the conventional wireless communication system, a DL/ULsemi-persistent scheduling (SPS) configuration is possible only in aprimary cell. However, in consideration of a case where carrieraggregation is introduced between BSs located in different regions and asecondary cell is frequently replaced, a plurality of SPS configurationsmay be preferably allowed.

In this case, only one SPS configuration on the secondary cell otherthan the primary cell may be allowed for each secondary cell group orfor all secondary cells. Further, regarding a configuration of an SPSperiod, a method of commonly setting a value used for each cell ispreferably applied to the secondary cell group or all of the secondarycells. The same value as that used for the primary cell may be appliedas the common value.

<PUCCH T×D Configuration>

In the conventional wireless communication system, a PUCCH T×D isconfigured for each PUCCH format. The T×D configuration based thereonmay be applied as follows.

1. A method of commonly configuring a PUCCH T×D in all cells for eachPUCCH format. For example, a PUCCH T×D configuration of a primary cell,may also be applied to other secondary cells.

2. A method of configuring a PUCCH T×D separately in each cell for eachPUCCH format.

It is allowed to perform suitable transmission according to each uplinkcell coverage, geometry environment, available PUCCH resource, etc.

3. A method of commonly configuring a T×D may be used for a specificsecondary cell group or all secondary cells. A specific configuration iscommonly applied to actively cope with a frequent change of thesecondary cell.

4. Only the primary cell may allow a T×D configuration only for a PUCCH.In case of the secondary cell, the T×D may be restrictively used since ageometry environment may be better than that of a macro BS.

<Configuration of ACK/NACK and CSI Simultaneous Transmission Mode>

In the conventional wireless communication system, a configuration of anACK/NACK and CSI simultaneously transmission mode is necessary only in aprimary cell. However, the following may be applied in the presentinvention.

1. The ACK/NACK and CSI simultaneous transmission mode may be commonlyset for all cells. In this case, a configuration of all cells mayconform to a configuration of the primary cell.

2. The ACK/NACK and CSI simultaneous transmission mode may be setseparately for each cell. It is allowed to perform suitable transmissionaccording to each uplink cell coverage, geometry environment, availablePUCCH resource, etc.

3. A method of commonly setting the ACK/NACK and CSI simultaneoustransmission mode may be used for a specific secondary cell group or allsecondary cells. A specific configuration is commonly applied toactively cope with a frequent change of the secondary cell.

4. A PUCCH may be transmitted only in the primary cell, and aconfiguration of the ACK/NACK and CSI simultaneous transmission mode maybe allowed.

<Configuration of PUCCH and PUSCH Simultaneous Transmission>

Conventionally, PUCCH and PUSCH simultaneous transmission is possibleonly in a primary cell, and thus a configuration of the PUCCH and PUSCHsimultaneous transmission is required only in the primary cell. However,in a future wireless communication system, the PUCCH and PUSCHsimultaneous transmission may be possible also in a secondary cell. Whenconsidering this, the following method may be applied in carrieraggregation.

1. A PUCCH and PUSCH simultaneous transmission mode (hereinafter, alsoreferred to as a simultaneous transmission mode) may be commonlyconfigured for all cells. In this case, a configuration of asimultaneous transmission mode of secondary cells may conform to aconfiguration of a simultaneous transmission mode of the primary cell.That is, if the PUCCH and PUSCH simultaneous transmission is allowed inthe primary cell, it is configured such that the PUCCH and PUSCHsimultaneous transmission is also allowed in the secondary cell. On theother hand, if the PUCCH and PUSCH simultaneous transmission is notallowed in the primary cell, it is configured such that the PUCCH andPUSCH simultaneous transmission is not allowed in the secondary cell.

2. The PUCCH and PUSCH simultaneous transmission mode may be configuredindependently for each cell. It is allowed to perform suitabletransmission according to each uplink cell coverage, geometryenvironment, available PUCCH resource, etc.

3. The PUCCH and PUSCH simultaneous transmission mode may be commonlyconfigured for a specific secondary cell group or all secondary cells. Avalue used for each cell may be commonly set for a specific secondarycell group or for all secondary cells.

4. The configuration of the PUCCH and PUSCH simultaneous transmissionmode may be allowed only in the primary cell.

<Configuration for a Case Where ACK/NACK Repetition is Allowed inCarrier Aggregation Situation>

Conventionally, a configuration of ACK/NACK repetition is not allowed incarrier aggregation. However, the ACK/NACK repetition is preferablyconfigured according to a situation of each cell when aggregating cellseach having a different feature.

1. An ACK/NACK repetition mode may be commonly configured for all cells.For example, the ACK/NACK repetition mode of a primary cell is equallyapplied to aggregated secondary cells.

2. The ACK/NACK repetition mode may be configured independently for eachcell. It is allowed to perform suitable transmission according to eachuplink cell coverage, geometry environment, available PUCCH resource,etc.

3. The ACK/NACK repetition mode may be commonly configured for aspecific secondary cell group or all secondary cells. A specificconfiguration may be commonly applied to actively cope with a frequentchange of the secondary cell.

4. The configuration of the ACK/NACK repetition mode may be allowed onlyfor a PUCCH transmitted in the primary cell. In case of the secondarycell, the ACK/NACK repetition may not be allowed since a geometryenvironment may be better than that of a macro cell.

<Configuration of ACK/NACK Transmission Mode for Multiple Cells/MultipleSubframes>

In the conventional wireless communication system, a multiple ACK/NACKtransmission mode (i.e., this implies that ACK/NACK for a plurality ofPDSCHs is transmitted at one time instance) is necessarily configuredfor all aggregated cells. For example, one of a channel selection methodusing a PUCCH format 1b and a method of using a PUCCH format 3 isconfigured.

If PUCCH transmission of a plurality of cells is allowed and each celltransmits multi-cell ACK/NACK for the plurality of cells or if themulti-subframe ACK/NACK for a plurality of subframes is transmitted, thefollowing method may be used.

1. The multiple ACK/NACK transmission mode may be commonly configured.For example, the multiple ACK/NACK transmission mode of the primary cellor the primary cell group may be equally applied to the secondary cell.

2. The multiple ACK/NACK transmission mode may be configuredindependently for each cell. It is allowed to perform suitabletransmission according to each uplink cell coverage, geometryenvironment, available PUCCH resource, etc.

3. The multiple ACK/NACK transmission mode may be commonly configuredfor a specific secondary cell group or all secondary cells. A specificconfiguration may be commonly applied to actively cope with a frequentchange of the secondary cell.

4. The channel selection method and the PUCCH format 3 may be allowed inan uplink of a primary cell, and only the PUCCH format 3 may be allowedin an uplink of a secondary cell.

5. The channel selection method and the PUCCH format 3 may be allowed inthe uplink of the primary cell, and only the channel selection methodmay be allowed in the uplink of the secondary cell.

According to the present invention, a configuration and transmission ofdownlink and uplink resources can be effectively used on the basis of apurposes, configuration type, and channel situation of a cell configuredin a situation where a plurality of cells are aggregated in one UE and acell to be used for actual scheduling of a BS and the UE.

FIG. 12 is a block diagram showing a wireless device according to anembodiment of the present invention.

ABS 100 includes a processor 110, a memory 120, and a radio frequency(RF) unit 130. The processor 110 implements the proposed functions,procedure, and/or methods. For example, the processor 110 provides a UEwith configuration information for PUCCH transmission. For example, itmay be informed whether a PUCCH can be transmitted only in a primarycell or can also be transmitted in a secondary cell. The processor 110allocates a plurality of cells to the UE, and transmits a firstparameter set and a second parameter set which are used to determinePUCCH transmission power according to a cell for transmitting the PUCCH.The memory 120 is coupled to the processor 110, and stores a variety ofinformation for driving the processor 110. The RF unit 130 is coupled tothe processor 110, and transmits and/or receives a radio signal.

A UE 200 includes a processor 210, a memory 220, and an RF unit 230. Theprocessor 210 implements the proposed functions, procedures, and/ormethods. For example, the processor 210 receives configurationinformation for PUCCH transmission, and transmits a PUCCH accordingthereto. Further, the processor 210 receives a first parameter set and asecond parameter set, determines transmission power of the PUCCH, andtransmits the PUCCH. The memory 220 is coupled to the processor 210, andstores a variety of information for driving the processor 210. The RFunit 230 is coupled to the processor 210, and transmits and/or receivesa radio signal.

The processors 110 and 210 may include an application-specificintegrated circuit (ASIC), a separate chipset, a logic circuit, a dataprocessing unit, and/or a converter for mutually converting a basebandsignal and a radio signal. The memories 120 and 220 may include aread-only memory (ROM), a random access memory (RAM), a flash memory, amemory card, a storage medium, and/or other equivalent storage devices.The RF units 130 and 230 may include one or more antennas fortransmitting and/or receiving a radio signal. When the embodiment of thepresent invention is implemented in software, the aforementioned methodscan be implemented with a module (i.e., process, function, etc.) forperforming the aforementioned functions. The module may be stored in thememories 120 and 220 and may be performed by the processors 110 and 210.The memories 120 and 220 may be located inside or outside the processors110 and 210, and may be coupled to the processors 110 and 210 by usingvarious well-known means.

What is claimed is:
 1. A method for receiving an uplink control channelin a wireless communication system, the method performed by a basestation and comprising: transmitting a first parameter set and a secondparameter set to a user equipment with which a plurality of cells areconfigured; and receiving the uplink control channel from the userequipment, wherein a transmission power of the uplink control channel isdetermined by using the first parameter set or the second parameter set,wherein if a cell in which the uplink control channel is received is aprimary cell, the transmission power of the uplink control channel isdetermined by using the first parameter set, wherein if the cell inwhich the uplink control channel is received is a secondary cell, thetransmission power of the uplink control channel is determined by usingthe second parameter set, and wherein the first parameter set includes aparameter for a path loss of the primary cell, and the second parameterset includes a parameter for a path loss of the secondary cell.
 2. Themethod of claim 1, wherein which of the first parameter set and thesecond parameter set is used depends on a cell receiving the uplinkcontrol channel.
 3. The method of claim 1, wherein the uplink controlchannel is a physical uplink control channel (PUCCH).
 4. A base stationcomprising: a radio frequency (RF) unit for transmitting and receiving aradio signal; and a processor operatively coupled to the RF unit,wherein the processor is configured to: transmit a first parameter setand a second parameter set to a user equipment with which a plurality ofcells are configured, and receive the uplink control channel from theuser equipment, wherein a transmission power of the uplink controlchannel is determined by using the first parameter set or the secondparameter set, wherein if a cell in which the uplink control channel isreceived is a primary cell, the transmission power of the uplink controlchannel is determined by using the first parameter set, wherein if thecell in which the uplink control channel is received is a secondarycell, the transmission power of the uplink control channel is determinedby using the second parameter set, and wherein the first parameter setincludes a parameter for a path loss of the primary cell, and the secondparameter set includes a parameter for a path loss of the secondarycell.
 5. The base station of claim 4, wherein which of the firstparameter set and the second parameter set is used depends on a cellreceiving the uplink control channel.
 6. The base station of claim 4,wherein the uplink control channel is a physical uplink control channel(PUCCH).